Collapsible mandrel particularly adapted for making, forming, and placing concrete piling.



N. C. JOHNSON.

COLLAPSIBLE MANDREL PARTICULARLY ADAPTED FOR MAKING, FORMING, AND

PLACING CONCRETE Puma.

APPLICATION FILED JUNE 4.1915.

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PLACING CONCRETE PILING.

APPLICATION FILED JUNE 4.1915.

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To all whom it may concern: I 2

Be it known that I, NATHAN C. JoHNso v, a citizen of the United States of America,

. and a resident of Englewood, county of Bergen, and State of New Jersey, have invented a certain new and useful Collapsible Mandrel Particularly Adapted for Making, Forming, and Placing Concrete Piling, of which the following is a specification.

This invention relates to improvements in collapsible mandrels; the mandrel herein described being particularly adapted for use 1n the making, forming, and placingof piles, or piling, of which the body is composed wholly or in part of concrete. ,The said'man'drel is particularly intended for use in the art of forming what are known as cast-ln-place concrete piles, wherein a rigid mandrel suitably constructed is placed within and covered by a thin shellof suitable material, the whole driven into the ground and the man drel collapsed and withdrawn, leaving the thin shell in the ground to form a mold for the reception of fluid concrete, which latter, after setting and hardening, forms the pile proper, as in the system of piling disclosed in U. S. Letters Patent to Raymond, Nos. 589,026 and 806,838. The applications of my improved apparatus are, however, not limited to the uses before specified, but may be applied to any purposes wherein it is desired to utilize a rigid mandrel, capable of 'later withdrawal, as, a force-resistant medium, or forming medium, in the placement or forming of molds, or forms, in the earth, for the reception of concrete which on setting and hardening will form a bearing column. or pile, whetheror not a covering, orshell shall be used therewith either as a temporary mold, or as one to remain permanently, both as a mold and as 'an integral and permanent part of the column, or pile, in the ground; also various other uses for my mandrel exist, and I do not'limit my invention to any particular use or uses.

The object of the invention is to provide simple eflicient means whereby a mandrel of the general type shown may be collapsed against severe external strains, as are often occasioned by the back pressure, or

inward pressure, of the earth through and into which the mandrel is driven by blows,

NATHAN C. JOHNSON, OF ENGLEWOOD, NEW JERSEY.

Specification of Letters Eatent.

oration.

ING, FORMING, AND

- PatentedFeb.29,i916.

- I Application filed June 4, 1915. Serial No. 32,173..

ing necessary for the easy removal of the mandrel.

A further object of my invention is to provide a simple, rugged and efficient construction whereby the collapsible mandrel may be expanded against pressure from Without,

instance, those wherein tapered bearings-are used for causing the expansion of the man-' drel, or for permitting its'collapse.

A further object of my invention is to provide means whereby the mandrel whenex-.

panded shall be held by the mutual inter-- actions of simple, rigid members in such state, even-against the collapsing action of severe forces such as might be exerted by the back pressure, or inward pressure of the earth, or bythe impact of the'driving hammer, until such time as it is desired to cause the collapse. of the mandrel; and to provide means whereby that collapse may be easily and quickly effected when desired. I

A further object of'my invention is to efi'ect the collapse of the mandrel positively, yet with'simple means and without multiplication of parts. v

A further object of my invention is to provide, 'in a collapsible mandrel for the purposes above indicated, such an arrangement of parts that the mechanism necessary shall be of such character as to admit of a lighter construction than isadmissible with other types of like apparatus, so that there shall be less-necessary mandrel weight with corresponding decrease of inertia of the apparatus, with resultant increase of penetration for a given blow, or, conversely, a lesser blow, as from a smaller and lighter 1' as from a drop hammer, such collapse be- 7 hammer, required for a given penetration,

with resultant economy of driving, or of equipment, or of both.

A further object of my invention is toi type shown as to admit of plasticconcrete being poured through the interior of the mandrel, thus admitting of the mandrel being used either without a shell, as in thosesystems of concrete piling wherein the fluid pressure, of the plastic concrete .is'frelied on to withstand the back pressureof theearth sustained before its Withdrawal'by .the.

' driven tube, or mandrel, or'permitting the use of the same fluid pressure with an unreinforced shell, by incasing the mandrel with such an unreinforce'd shell. before driving,

fitting the mandrel with a removable point which remains with the shell permanently in. the ground after driving, the collapsing of the mandrel enabling its ready .withdrawal from the shell, and the plastic concrete, passing through the mandrel into the shell as the mandrel is withdrawn, aiding the shell to withstand the back-pressure of the earth.

The accompanying figures illustrate the general features of my invention and its application as stated above. I

In said drawings :v Figure 1 shows a sec tional elevation of a collapsible'mandrel embodying my invention, and driving head,

the parts of the mandrel being shown in collapsed position, and two elements only of the mandrel being shown, though in general the mandrel will be composed of a much larger number of similar elements. Fig. 2

shows a transverse section of the casing-and .mandrel on the line 'X-X of Fig. 1. Fig.

3 shows a fragmentary vertical section of one of the elements of the mandrel, in relaxed condition. Fig. 4 is a view similar to Fig/3, but showing the parts in a partly expanded position. Fig. 5- is a further simi-- cordance with my invention, a casing sur-;

rounding such mandrel being also shown in section; and Fig- 9;-isa similar view except that a taper casing and corresponding taper mandrel are shown. Fig. 10 is a transverse section, and Fig. 11 a fragmentary longitudinal section, of. an alternative form of mandrel; .and F1g.'12 1s a transverse section of a' still further alternative form of mandrel. I

I will particularly describe my invention with reference to its use in the making, forming, and placing of castein-place concrete piles; but it will be understood that in so doing I do not limit myself to such particular use of the invention.

Fig. 7

The mandrel, or core, as it is sometimes called, whatever its sectional-form, may be made of any number of segments from two up; and I do not limit myself to the particular number of segments ofwhich-the mandrel, orcore, is-made; theparticular circular section mandrel, or core, herein illustrated and described being made-of three segments. Segmental mandrels, or cores, have been used heretofore in the art of concrete piling, but, as made and used heretofore, the expansion of segments, or leaves, of

the mandrel, or core, I has usually been broughtabout by means of wedges mounted upon aninterior spindle; in which construction the blows of the hammer by which the pile casing is driven, areJpartly transmittedto the-segments, or leaves, of the core, or

mandrel, through the medium of the bearing a of such wedges against the leaves of the mandrel; and as the taper of these wedges is usually such as to make this transmission of energy least efiective, the driving effect of the hammer, as evidenced in penetration of v the mandrel,- is decidedly imperfect. Further, in mandrels, or cores, of this old type, the back pressure or inward pressure, of theground, when exerted against the segment, or leaves, must, to be in equilibrium, be transmitted transversely of the core,'through the'wedge bearings; and'this pressure, often amounting to many tons at each wedge-bearing, exerts 'an upward thrust on the central wedge-spindle, with the result that there is not only a constant tendency'to collapse, which'must-be forcibly resisted by appropriate means, "but further, this upward tendency ofthe central 1 interior spindle causes the driving head to separate from the -leaves,.with the result that not only is driving progress consider- I ably and appreciably delayed, through the internal consumption of energy in these various actions and reactions, but there is also a constant disruption of the component parts of the core under theim'pact of the hammer blows. To resist this impact-,therefore, the severalparts 'of the core must be made extremely massive; and this necessity results not only in a high inertia factor for the core, which inertia has to be overcome each and every time the core is struck and before penetration can result, but it has the further disadvantage of high-value internal reactions, tending to disrupt the several parts of the core; and of high first cost and depreciation and transportation charges. These disadvantages I overcome in my invention.

In carrying out my invention I employ toggle-jointmechanism with special form and functions for the levers, in common with those functions usual to them.

Referring first to Figs. 1 and 2, reference shown particularly in Fig. 7, and has at its outer end massive trunnions F.fitting within suitable bearing-sockets of the bearing members D; while at its inner end each such lever F has a board bearing F whereby it is pinned to the center spindle E. On the underside of each such lever F and integral with 'it, is an extended rib N having its forward edge N sharpened to a wedge point. From Fig. 2 it will be apparent that these wedge-points N are adapted to enter the slots between two adjacent leaves A, and thereby to force such leaves outward in addition to the powerful toggle action when the arms of the levers F are forced down by depression of the center spindle It will further be apparent that in this mandrel there is a double action, first by the levers F acting as toggles, and then by'the wedge-points N acting as wedges, tending to force the mandrel leaves A outward,

when the levers F are forced down. This will be especially apparent from comparison of Figs. 1, 3, 4 and 5. By comparison. of Fig. 1 with Fig. 3 it will be seen that the first effect of downward motion of spindle E is to force the trunnions F of thelevers F-back to the outward extremities of the bearing recesses in the bearing members D; further motion downward of the levers F forces those members D outward, and with duced between the adjacentedges of adjacent leaves A, as shown in. Fig. 6. When the leaves'F. are in horizontal position, as

shown in Fig. 4, the toggle action of those levers has reached its maximum; and as those levers F move downward below the horizontal position, the toggles themselves are collapsed; but the wedges N are forced still farther forward, or outward, between the adjacent edges of the mandrelleaves A, as shown in Figs. 5 and 6, until they bear, either against such edges of leaves A, or against the corresponding edges of the bearing members D, or both, thereby'exerting a very powerful wedging action tending to hold the mandrel leaves outward; the toggles themselves being at such time partially collapsed and with no pressure on them. It will be evident that. any number of mandrel leaves. or segments, with such wedges N thus thrust between them, will be in stable equilibrium so far as inward thrust is concerned, and that the tendency to collapse due to external pressure will be resisted by a solid block, of material N in purecompression, and with no pressure on pins, or pivots, or bearings-a most advantageous condition; and it willfl'als'o be evident that the insurance of a thorough and effective penetration of this blockof material, N, is

the toggle arms, actuated-by the depression of the spindle E, as compared to that of the resisting wedges N pressedagainst by the leaves A. It is evident that this isv a very powerful lever system rendering-certain andpositive a proper expansion-of-the leaves.

It is contemplated thatjthe wedges shall be of such dimensions that when those wedges are in the extreme outward position the pressure of the mandrel leaves will be against the-parallel faces of those wedges, so that the pressure of theleaves on the Wedges exerts no tendency whatever to thrust such wedges inward again. However, the angle of the wedges is :so small that pressure of the leaves on those wedges, if exerted upon the oblique faces of the wedges,'would be exerted at an angle much smaller than the critical angle of the'friction and so would exert no tendency to press the wedges inward. Moreover, it will be :noted that if for any reason the wedges brought about by the relative lever arms of f hearing pieces D, necessitating an outward thrust on the leaves; and rise of the toggle.

levers to dead center would be strongly resisted not only by the weight of the center piece Eand the latches G connecting the driving head with the leaves, but also by the inward pressure of the earth. This constitutes a double insurance against unintended collapse. g

' When it is desired to effect collapse of the mandrel the central spindle E is raised, and it will be obvious that like actions take place in reverse direction with equal power an efficiency.

The'driving head, C, is suitably connected to the central spindle'E, and is also provided, in practice, with a wooden driving block C which receives the blows of a hammer. This head C is also provided with slings C whereby the spindle E may be raised when it is desired to collapse the mandrel.

In practice, the mandrel is usually used (though not necessarily) with a casing I '(Fig. 8) or I (Fig. 9); casing I being straight while casing I is tapered; the mandrel being modified in construction as shown in Fig. 9 when it is to be used with a tapered casing.

In fitting the mandrel for the reception of the casing, the collapsed mandrel is lifted into the pile driver guides or leads, usually by suitable cables attached to the hammer by which the mandrel and casing-are to be driven, and the point of the mandrel is then dropped upon a suitable support, such 'as a timber, from a short height. The inertia of the driving head C and the spindle E then serve to cause relative'motion between the spindle E and the leaves A so that the mandrel'is fully expanded- The driving -head C is provided with dogs G which "then engage notches A in the mandrel leaves A. The expandedmandrel as a unit may then be lifted again into the leads so that the casing or shell I (Fig- 8,) or I (Fig. 9) may be slid over the mandrel in sections and drawn into position by suitable means. In the construction herein shown, however, it is possible to effect the advantageous alternative of placing the sections of the casing F are'readily removable from engagement or shell easily outside of the mandrel be fore expansion and expanding the mandrel by the procedure outlined above; the mandrel in this latter case'being powerfully expanded against the casing or shell I with the result that the casing is tightly bound to the mandrel by friction. The. proper engagement of the'dogs Gzwith the recess A may be .insured by. proper alining means such as the dowels-K entering recesses C in the driving head 0. These dowels, however, are not the only' means which may be, used for this purpose, and are shown as con-.

from the mandrel leaves A and then lifting the'driving head by means of the slings C, whereupon the spindle E is lifted, toggle levers F are raised and therebyv the wedges N. are .Withdrawn from between the leaves of the mandrel, and the trunnions F of the toggle levers moved to the position shown in Fig. 1, so entirely collapsing the mandrel and permitting its withdrawal. ing members D are provided with hook lugs D and with corresponding bottom lugs D" .whereby the trunnions F are, in practice,

confined, yet in such manner-that the levers with the bearing pieces D when the leaves A are. by proper means moved out at right angles from the center line of the spindle E. In other words, when the mandrel is in relaxed position, the leaves A of the mandrel may be separated from the toggle mechanism by moving the trunnions F of the levers F- through the -gaps between the-lugs and v Similarly,,itis easy- -to reengage the mandrel leaves. with the The bear them outward radially, assing D of those leaves.

toggle'mechanism; But while it is easy to out fear of such disengagement occurring, because any upward pull on thedriving head C when the toggle mechanism is relaxed, and themand'rel collapsed, draws the trunnions F into the recesses in the under sides of the lugs D, the leavesvof the mandrel then hanging securely from those trunnions. v v

It is obviouslyv immaterial whether the wedges NN of the toggles bear against the sides of'the leaves themselves, or against the sides of the bearing members D,- sinoe these bearing members D' are to be considered as being, functionally, parts of the" leaves themselves.

Since the mandrelle'aves form a nearly complete cylinder, or cone, as the case may be, it is perfectlypracticable to drive the mandrel into the ground, without first surrounding that mandrelwith a casing;

and then, when the mandrel has been drivento a suitable depth, it'may be withdrawn and the hole in the earth filled with concrete; or, the concrete required -to form the pile may be run in before the mandrel has been removed; (for the mandrel is largely open, inside, affording ample space for the flow of concrete) and then, before the concrete has set, the mandrel maybe removed;

in which case the concrete will remain in the hole, the point B may, or may not, re-

main inthe holeas desired, and according -to the constructionof shell, or mandrel, or

both, which is employed; And of course, when a caslng is used, this caslng may be filled with concrete while the mandrel is inplace, and then the mandrel removed before the concrete has set. V

It is not necessary that the toggle levers F'be pivoted across the gaps between the leaves. In Fig. 10 I show a construction wherein the toggle levers, there designated by numerals F, are pivoted at the centers of the leavesA and wherein the wedges N N" are structurally separated from the toggle levers F but are operated by the. It is obvious that the same spindle E operation of this combined toggle and wedge mechanism shown in Figs. 10 and 11 is the same as that of the mechanismshown in the previous figures.

' In the further alternative constructidn shown in Fig. 12, the wedges, N", N"?, are integral with the toggle levers F, but are extended laterally from the said levers F 70 engage and disengage the levers of the mandrel with the toggle mechanism, nevertheless the mandrel may be handled with-.

since the latter are pivoted, at the centers of the mandrel leaves A the edges of the mandrel leaves A being preferably nonradial, asindicated in Fig. 12.

1. An expansible and collapsible mandrel comprising a plurality of outwardly and inwardly movable leaves, toggle mechanism for moving said leaves out and in, means for actuating such toggle mechanism and means actuated by said actuating means for relieving the toggle mechanism of pressure and for holding the leaves outward.

2. Anexpansible and collapsible mandrel comprising a plurality of outwardly and inwardly movable leaves, toggle mechanism for moving said leaves out and in, wedge means for relieving the toggle mechanism of pressure and for holding the leaves out ward and means' for actuating said toggle mechanism and wedge means.

3. An expansible and collapsible mandre comprising a plurality of outwardly and inwardly movable leaves, toggle mechanism for moving said leaves out and in, means for actuating such toggle mechanism, and wedge means actuated by said toggle mechanism for relieving the toggle mechanism of pressure and for holding the leaves outward. 4. An expansible and collapsible mandrel comprising a plurality of outwardly and inwardly movable leaves, toggle mechanism for moving, said leaves out and in, means for actuating such toggle mechanism and wedge means actuated by said actuating means for relieving the toggle mechanism of pressure and for holding the leaves outward, said wedge means comprising wedges adapted for insertion between adjacent leafedges.

5. An expansible and collapsible mandrel comprising a plurality of outwardly and in- .wardly movable leaves, toggle mechanism for moving said leaves out and in, means for actuating such toggle mechanism, and wedge means actuated by said toggle mechanism for relieving the toggle mechanism of pressure and for holding the leaves outward, said wedge means comprising wedges adapted for insertion between adjacent leaf-edges.

6. An expansible and collapsible mandrel comprising a plurality of outwardly and in-- wardly movable leaves, toggle levers for moving said leaves out and in, said levers provided with wedges arranged to be thrust between adjacent leaf-edges during the outwardly forcing action of the toggle levers and means for actuating said toggle levers.

7. Anexpansible and collapsible mandrel comprising a plurality of outwardly and inwardly movable leaves, toggle levers for moving said leaves out and in, said levers provided with wedges arranged to be thrust between adjacent leaf-edges during the outwardly forcing action of the toggle levers, and to remain between said leaves after said toggle levers pass the dead center, and

means for actuating said toggle levers.

8. An expansible and collapsible mandrel comprising a plurality of outwardly and inwardly movable leaves, toggle levers for moving said leaves out and in, said levers provided with wedges arranged to be thrust between adjacent leaf-edges during the outwardly forcing action of the toggle levers, and to be thrust still-farther forward between said edges by motion of the toggle levers beyond the dead center, and means for actuating said toggle levers.

9. An expansible and collapsible mandrel comprising a plurality of outwardly and inwardly movable leaves, toggle levers for moving said leaves in and out, provided with approximately right-angle extensions provided on their outeredges with wedge portions arranged to be inserted between adjacent leaf-edges by expanding motion of said toggle levers, and means for actuating said toggle levers.

10. An expansible and collapsible mandrel comprising a plurality of outwardly and inwardly movable leaves, toggle levers for moving said leaves in and out, provided with approximately right-angle extensions provided on their outer edges with wedge portions arranged to be inserted between moving said leaves in and out, comprising means for holding said leaves in the expanded position, and which, when the mandrel is expanded, is free from inward thrust due to pressure on, or shock applied to, said leaves, and comprising also operating means which is relaxed and free from pressure when the mandrel is completely expanded.

12. An expansible and collapsible mandrel comprising a plurality of outwardly and inwardly movable leaves, mechanism for moving said leaves in and out, comprising means for holding said leaves in the expanded position, and which, when the mandrel is expanded, is free from inward thrust due to pressure on, or shock applied to, said leaves, and comprising also toggleoperating mechanism which is relaxed when the mandrel is completely expanded.

13. An expansible and collapsible man drel comprising a plurality of outwardly and inwardly movable leaves, each provided with lugs on its inner face having a bearing recess between them, levers for said leaves Intestimony whereof I have signed this having trunnions mounted in such bearing specification in the presence of two subscribrecess, the said lugs of said leaves having ing Witnesses.

gaps for the lateral disengagement of the NATHAN C. JOHNSON. :leaves from said lever trunnions, and'mea'ns Witnesses: I

connected to said levers for actuating the H. M. MARBLE,

same. 1). A. DAVIES. 

